simulation: allow to use solve divergence dialog when state is calculating

This avoid annoying messages that someone else modified the document, if the
user knows we is going to have a divergence, he should be able to use the dialog
immediately.

bt5/erp5_base/WorkflowTemplateItem/portal_workflow/delivery_causality_workflow/states/calculating.xml

@@ -32,6 +32,7 @@
                 <string>diverge</string>
                 <string>solve_automatically</string>
                 <string>solve_divergence</string>
+                <string>solve_divergence_action</string>
                 <string>start_building</string>
               </tuple>
             </value>